Lionel Messi's father and agent has told La Liga that the 700m euro (£624m) release clause in the forward's Barcelona contract is not valid.
Jorge Messi said in a statement that his son's release clause expired at the end of last season.
However, La Liga has responded by insisting that is not the case.
Spain's top-flight competition said in a statement: "La Liga has responded to the message received from the representatives of the player Leo Messi.
"In its response, La Liga notes that their interpretation of the contract is out of context and far removed from its literal state. La Liga reiterates its statement published on 30 August."
In the letter sent on Friday, Messi's father argued that his son's contract does not specify a date when the option to leave must be exercised, only that it must be done at the end of the campaign.
Manchester City are favourites to sign the six-time Ballon d'Or winner should he leave and Font, who is hoping to take over from current president Josep Bartomeu, believes the chance for him to link up with ex-Barca boss Pep Guardiola is a huge draw for the player.
Meanwhile Barcelona forward Luis Suarez has agreed to join Juventus.
Suarez will move to Serie A on a free transfer - or perhaps a nominal fee - if he can negotiate his release from the Spanish giants.
The Uruguayan has a year to run on a contract he signed in 2016 but if he played 60% of games during 2020-21 it would be extended for another year.
Suarez would be happy to be paid off with one season's wages.